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Unformatted text preview: Problem 4: Consider a dislocation loop: a circular dislocation in a plane. The Burgers vector is the same everywhere inside the loop. Assume it lies in the plane of the loop. (a) Show that the dislocation is an edge dislocation at precisely two points on its circumference, and is a screw dislocation at precisely two other points. (b) Describe how the homogeneous expansion of the loop leads to plastic deformation. Problem 5: Cu and NaCl are both crystalline solids. An NaCl crystal has a strong tendency to take the form of a cube while a Cu crystal has little preference for a particular shape (in fact, given complete freedom of shape, it would tend to be nearly spherical). Explain this behavior in terms of the surface structure....
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- Spring '07